The present invention relates to the arrangement of an X-ray exposure system for forming the duplicate of a fine mask pattern on a semiconductor substrate through the soft X-ray lithography using synchrotron radiation.
X-ray exposure apparatuses for carrying out X-ray duplication by synchrotron radiation (hereinafter simply referred to as "SR") have hitherto been arranged as shown in FIG. 1. That is, the SR emitted from a synchrotron (storage) ring 1 is taken out through a plurality of beam ducts 2, and an exposure apparatus 3 is provided at the end of each beam duct 2. Such an arrangement has been reported e.g. by R. P. Haelbich et al. (members of IBM), at the 3rd national conference on synchrotron radiation instrumentation held on Sept. 12 through 15, 1983.
In the arrangement of FIG. 1, the exposure stations 3 are located around the synchrotron ring 1 separatedly, and therefore a plurality of facilities and man powers are required to operate the respective exposure stations. Moreover, such an arrangement is inconvenient for utilizing the exposure stations 3.
Generally speaking, in the case where a circuit pattern is formed on a silicon wafer by an X-ray exposure apparatus, time required for loading and unloading the silicon wafers in the X-ray exposre apparatus and time required for aligning an X-ray mask with the silicon wafer are far longer than time required for irradiating the X-ray mask and silicon wafer with SR. Further, the SR is emitted continuously from the synchrotron ring 1. Accordingly, in the arrangement of FIG. 1, the SR passes through a beam duct 2 wastefully over a long period other than an exposure time, and thus each exposure stations 3 is considered to be low in utilization efficiency of SR.
Further, it is needless to say that the arrangement shown in FIG. 1 is inconvenient for utilizing the exposure stations 3, as compared with the case where the exposure stations 3 are concentrated in a place.